1. Field of the Invention
The present general inventive concept relates to a front surround sound reproduction system using directional speakers, and more particularly, to a directional speaker system and an automatic set-up method thereof, whereby a steering angle of the directional speaker system is automatically set up.
2. Description of the Related Art
Conventionally, front surround sound reproduction systems create a stereoscopic feeling from a front speaker array without side or rear speakers using signal processing technology.
Front surround sound reproduction systems form sound beams from a surround channel signal using a directional speaker array and emit the sound beams to the wall so that reflection sounds reflected from the wall reach a listener. Thus, the listener can feel a stereoscopic effect due to the reflection of sounds as if the sounds are heard from side and rear speakers.
Front surround sound reproduction systems use a virtualizer, a rear reflector, and a directional speaker. Thus, front surround sound reproduction systems are classified into directional speaker systems and array-type sound systems.
Stereo sound performance of the directional speaker systems or the array-type sound systems depends on how to appropriately control a sound beam direction according to a listener and listening space. Control variables are an angle, strength, and arrival time difference of sound beams, and vary according to a geometric structure and material of the listening space. However, a set-up method for general users, who do not have technical knowledge of directional speakers and so are unable to easily set up and use the directional speaker systems or the array-type sound systems, is required.
A technique related to an automatic set-up method of an array-type sound system is disclosed in WO 04/066673 (filed 19 Jan. 2004 entitled SET-UP METHOD FOR ARRAY-TYPE SOUND SYSTEM).
FIG. 1 illustrates an array-type sound system using a conventional automatic set-up method. Referring to FIG. 1, a controller (not shown) controls C (center), Ls (Left surround), and Rs (Right surround) channel signals belonging to surround channels among 5.1 channels to have straightness in different directions. The controller controls a small aperture speaker array 10 to form sound beams 12-1 and a middle aperture speaker (not shown) to reproduce a middle and low frequency signal. The small aperture speaker array 10 forms sound beams 12-2 having straightness at appropriate angles so that surround channel signals are focused on the ears of a listener 13 after been reflected from side and rear walls 161. Thus, sounds reproduced by the small aperture speaker array 10 are reflected from the side and rear walls 161 so that the listener 13 feels a stereoscopic effect. The array-type sound system illustrated in FIG. 1 determines a first reflection angle and a distance from a reflection surface using a Sound Pressure Level (SPL) technique.
Thus, an automatic set-up method of the array-type sound system illustrated in FIG. 1 uses the SPL as a technique of emitting a test signal and determining a reflection angle of the test signal.
However, the conventional automatic set-up method illustrated in FIG. 1 has a disadvantage in that the set-up process fails when complicated reflection or diffusion occurs in an actual space, since the conventional automatic set-up method tries to measure a reflection position/angle with only the SPL. In addition, since the conventional automatic set-up method illustrated in FIG. 1 uses test signals, such as a Maximum Length Sequence (MLS), a user may find the set-up process very annoying.